The twin models have a secondary lock
When the door is closed for the main lock, turning the key of the secondary lock, the cylinder stops rotation of the main lock key, which controls the deadbolts.
This is a useful solution for preventing, if necessary, access to the people who hold the key of the main lock.
EXCLUSIVE LOCKING SYSTEM VIGHI’S APPLIED TO TOP DOORS
The deadbolts do not come out from the lock, but they are distributed along the bar of the leaf and are self-locking.
n.6 movable deadbolts
n.4 reinforcing omega